This invention relates to an apparatus for attaching a load bearing line to a helicopter. More particularly, the invention relates to an apparatus for attaching a load bearing line to a helicopter to substantially eliminate the imposition of destabilizing moments on the helicopter due to the side-to-side swinging of a cargo load supported by the helicopter.
Helicopters have been found useful in both military and civil applications. Among the many uses that helicopters may serve, the helicopter due to its hovering capability has been found particularly suitable for use as a crane for lifting various types of structures both on land and offshore. In other applications, because of its maneuverability, the helicopter has been utilized and lift and transport cargo from one location to another.
In order to utilize a helicopter as a flying crane or a cargo transporting vehicle, a cargo hook has been provided on the underside of the helicopter's fuselage for engaging a loop at the end of a cable connected to the load to be transported by the helicopter. To minimize the impact of the cargo hook installation on the structural design of the helicopter, the cargo hook is usually mounted rigidly to the underside of the helicopter. Thus, a load that is lifted by a helicopter at the end of a line that is connected to a helicopter by a rigidly mounted cargo hook will impose forces on the helicopter that pass through the point of attachment at the bottom of the fuselage.
It has heretofore been found, and it can readily be appreciated, that when a load that is being lifted by a helicopter in the aforementioned manner begins to swing from side to side that destabilizing moments will be created about the center of gravity of the helicopter. The creation of destabilizing moments makes the helicopter more difficult to control and may limit the amount of lead that can be safely lifted by the helicopter.